Semiconductor device fabrication typically makes use of electrochemical processes such as electroplating for defining and/or creating the structures of the semiconductor devices. During the electrochemical processes, a wafer typically needs to be protected by means of a special form seal (typically a seal ring) against wetting of the wafer backside and the wafer edge by the process liquid. By doing so it is intended that the chemical process reacts at the chip front side only.
In order for the form seal to work efficiently, the wafer must have a relatively precise position and orientation when being in contact with the form seal. An incorrect orientation of the wafer with respect to the form seal may lead to an erroneous processing of the wafer, which goes along with discarding the erroneously processed wafer. A wafer that has been incorrectly loaded and has an incorrect orientation relative to the form seal also negatively affects subsequent wafers, because a contaminated form seal loses its tightness. This may lead to unscheduled downtimes of wafer production equipment and damage to expensive plant sections.